Process of making varnish.



7 UNITE STATES PATENT OFFICE.

AUGUST P. BJERREGAARD, ,oF- MOUNT VERNON, NEW YORK, ASSIGNOR TO CHARLES w, COOPER, on NEW YORK, N. Y.

PROCESS OF MAKING ,VARNISH.

SPECIFICATION formingpart of Letters PatentNo. 629,329, dated July 25, 1899. Application filed m 9, 1897. Serial No. 644,009. on specimensi) T0 at whom it may concern:

' Be it known that I, Aucusr P. BJERRE- GAARD, a citizen of the United States, residing at Mount Vernon, Westchester county, New York, have invented a certain new and useful Improved Process of Making Varnish, of which the following is a full, clear, and exact description.

My invention relates to an improved process for the manufacture of those varnishes which consist, chiefly, of linseed-oil or other fatty oils and copal-gums, and by the term copal I include amber, which is simply a very hard and highly-fossilized copal, and those hard copals sometimes] known as anime, as Well as the other gums known as copals.

Heretofore in the manufacture of varnish composed chiefly of the above elements the steps have been as follows: First, the gum is fused in one receptacle and the oil heated inanother receptacle; second, the hot oil is poured into the fused gum and the mixture boiled until it responds to the desired test and then allowed to cool.

The disadvantages of the above well-known and common process are manifold, some of them'being the necessity in making a good varnish of employing only the larger lumps of gum, while the 'finer lumps are discarded for the reason that the heat required to soften and fuse the larger lumps would if fine particles were used char or burn the latter, and thereby result in injury to the color and quality of the finished product. Another disadvantage is' the necessity of the constant and. watchful attention of a skilled operator to prevent the charring and burning during the fusing or running process of the gum another,

the limited capacity of the output of a single same, and thereby injuring the color and quality of the finished product. By reason of the fact that the danger of burning the gum is avoided the operator is relieved of the necessity of guarding against that particular cause of injury and may occupy all his time attending to other details, thusenabling a greater production of the finished product by a given number of skilled operatives than can be made by theold process. Further, where it is customary by the old process to make the varnish in comparatively small batches the size of the batch made by my process is limited only by the capacity of the apparatus used, which may be as large as desired, as distinguished from the limited capacity of a feasible apparatus used under the old process.

In carrying out my invention I first mix raw copal-gum with linseed or other suitable fatty oil (with or without the addition of a suitable drying agent-a, for example,.borate of manganese) in the proportions, for instance, of about four (4) pounds of copal to one (1) gallon of oil for a wearing-body or outside-surface varnish; but the proportions are subject to variation, according to the kind and quality of the gum and oil used or varnish to be made. They are about the same as they would be in the ordinary process under similar conditions and are to be determined with more exactness by the judgment of a skilled operator, whose experience in the old process will guide him equally well in this. The gum is preferably finely ground, (although lumps may be used,) and the oil is preferably unboiled. The mixture is placed in a suitable kettle and subjected to heat,

which soon softens the gum and at first imparts to it a tendency to rise to the surface, and if. the kettle is an ordinary one the gum should then be pressed or kept under the surface by any suitable means. After the gum is sufficiently softened or quite melted by the heat the mass should be thoroughly stirred to mix the ingredients, as well as to facilitate the escape of'the vapors generated, the heating being meanwhile continued until the ordinary tests applied to samples show that'it has been sufficiently boiled, and then the heating is stopped and the varnish is allowed to cool naturally or artificially. It is then liquid shall respond to a satisfactory varnish.

test, which will occur at about 600 Fahrenheit. During the latter part of the heating it is desirable to stir the mass, as previously described. When the varnish is completed, cool and thin the mass in the manner hereinbefore described. The temperatures specifically mentioned are only relative and may vary substantially, yet any one skilled in the art will by following the directions herein given produce in a simple, safe, and effective manner a satisfactory product. The time required to carry out this process may vary greatly, depending upon the area of heatingsurface relative to the quantity of the mate-.

rial acted upon and the intensity of the heat employed.

Although I have obtained good results in this process with oil that has been previously boiled, my experience has taught me, nevertheless, that if the oil has previously to the mixing with the raw gum been too much boiled, as shown by the results, more or less of a gelatinous or soft rubbery mass is apt to be produced, which tends to impair the product or render it entirely unfit for varnish.

a thicker varnish the boiling may be still further continued.

Any means that will insure the complete melting-and thorough mixture of the gum in the oil before the latter is too much boiled will, with a proper continuation of the heating, after said melting and mixing (which any one skilled in the old process can judge of) insure the success of the operation.

To reduce the varnish to a suitable consistency to enable it to be applied with a brush, turpentine or other suitable thinning agent may be added thereto in the ordinary manner.

Instead of mixing the gum and oil together cold and heating them simultaneously I find that it is practicable to lnakethe varnish by first heating the oil, next gradually introducing the cold gum into the hot oil, thus melting it therein, and then heating the mixture until it responds to the desired tests, as above described.

By fatty oil I mean to include any fatty oil from which, in combination with copal, a varnish can be produced that can be made to dry. 7

\Vhat I claim is The process of making varnish of copalgum and fatty oil, said process consisting in mixing a raw copal-gum in a suitable fatty oil, next applying heat until the gum in the oil becomes fused, and. next applying an in creased degree of temperature until the mixture becomes varnish.

Signed at New York, in the county of New York and State of New York, this 26th day of 

